This invention concerns an electrical power generating arrangement from which the electrical power output is to be connected to the electrical mains.
The electrical power generating arrangement may be included in a combined heat and power system (CHP), though it need not necessarily be.
In some known CHP systems the electrical generator feeding its output into the electrical mains or grid is rotated at substantially constant speed by a reciprocating internal combustion engine giving a substantially constant speed rotary output driving the generator. Since the engine rotates at a substantially constant number of revolutions per minute (r.p.m.) whatever the electrical power demand from the generator by an external circuit being supplied, the engine is not necessarily operating at optimum efficiency which optimum efficiency may occur at a lower r.p.m. than the aforesaid constant r.p.m. for low power demand or at a higher r.p.m. for higher power demand. Also best advantage cannot be taken of using high revving high performance engines produced for motor vehicles.